面试题33. 二叉搜索树的后序遍历序列

[fireairforce]

用递归去judge即可:

/**
 * @param {number[]} postorder
 * @return {boolean}
 */
var verifyPostorder = function(postorder) {
    if (postorder.length === 0) {
        return true;
    }
    return verify(postorder, 0 , postorder.length - 1)
    function verify(seq, start, end) {
       if(start >= end) {
           return true;
       }
       let i = start, j = end - 1;
       while(i < end && seq[i] < seq[end]) {
           i ++;
       }
       while(j >= start && seq[j] > seq[end]) {
           j --;
       }
       if(i < j) {
           return false;
       }
       return verify(seq,start,i - 1) && verify(seq,j + 1,end - 1);
    }
};